Program providers such as television networks or stations, studios, Internet broadcasters or service providers, cable operators, satellite operators and the like, deliver video programming to consumers via digital signals. Devices and signals involved in the delivery of digital video programming to consumers may comply with various industry specifications, or standards, which have been promulgated by groups desiring, among other things, to ensure interoperability between systems and devices that deliver the digital video programming.
The Digital Display Working Group (“DDWG”), for example, has published a document entitled Digital Visual Interface, Revision 1.0 (hereinafter referred to as the “DDWG Specification”), which sets forth an industry standard for a physical digital visual interface (“DVT”), and a protocol for electrical signaling thereon, between a personal computing device and a display device. The DDWG Specification is hereby incorporated by reference in its entirety for all purposes, as if set forth in full herein. Likewise, the Electronic Industries Alliance (“EIA”) and the Consumer Electronics Association (“CEA”) have together promulgated a standard entitled “EIA/CEA-861,” published in January, 2001 (hereinafter referred to as the “EIA/CEA-861 Standard”), which defines video timing requirements, discovery structures, and data transfer structures used for implementing digital interfaces on digital televisions or monitors. The EIA/CEA-861 Standard is also hereby incorporated by reference in its entirety for all purposes, as if set forth in full herein.
Both the DDWG Specification and the EIA/CEA-861 Standard address mandatory uses of a data structure known as the Video Electronics Standards Association's (“VESA”) Extended Display Identification Data (“EDID”) data structure (hereinafter referred to as the “EDID Data Structure,” which is described in detail in a document published by VESA entitled “EDID Standard, Version 3, November, 1997, incorporated by reference in its entirety for all purposes, as if set forth in full herein). The EDID Data Structure is stored by display devices such as digital television displays and monitors, and defines, among other things, data formats and timings used to carry information, such as video programming, from source devices, such as cable or terrestrial set-top boxes, digital video cassette recorders (“VCRs”), computers, and digital video disk (“DVD”) players, to the display devices, and further defines the display devices' capabilities to receive and render data in such data formats/timings.
Among other things, the DDWG Specification and the EIA/CEA-861 Standard require that source devices read the EDID Data Structure from display devices (the EDID Data Structure may be transmitted from display devices to source devices over physical links such as I2C buses, for example), to determine data format/timing capabilities supported by the display devices. Neither the DDWG Specification nor the EIA/CEA-861 Standard, however, currently mandates how source devices use information from the EDID Data Structure to select data formats/timings for sending video programming to display devices.
Customer dissatisfaction with the performance of either source devices or display devices is a danger when display devices present inaccurate EDID Data Structures—for example, the use of information obtained from reading inaccurate EDID Data Structures may result in the source devices sending video using data formats/timings not supported by, or optimal for, the display devices.
There is, therefore, a need for a method and apparatus for verifying a video format supported by a display device, which is able to provide a robust consumer experience even in the instance where the display device provides an inaccurate EDID Data Structure.